Add JS module detection rewriting

[tw4l]

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Description

This PR modifies pywb to detect and rewrite JS modules. Global overrides are imported in modules via a new _wb_module_decl.js static file.

This also bumps wombat to 3.4.2.

Motivation and Context

JavaScript modules were previously not detected, which caused errors in replay for sites that use them.

Types of changes

• [X] Replay fix (fixes a replay specific issue)
• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have added or updated tests to cover my changes.
• [X] All new and existing tests passed.

[ato]

I tested this on a site we've been handling trouble with (https://www.aucyberexplorer.com.au/). Unfortunately this site uses JavaScript modules that don't start with import or export so the is_module check doesn't trigger. It looks like wabac.js handles this problem by introducing a new esm_ modifier so the detection is based on the context in the referencing page rather than the contents of the script file alone.